Seam



2,8%,0491 Patented Dec. 3l., 1957 dee SEAM

Arnold Krohn, Whitman, Mass. Application March 17, 1953, Serial No. 342,844

1 Claim. (Cl. 112-Z62) This invention relates to sean-1s and has for its principal object to provide a seam formation which is both utilitarian and decorative. Further objects are to provide a seam especially for leather goods, such as shoes, pocketbooks, belts and analogous leather wear which not only provides for a wide range of decorative treatment to enhance the appearance of the article but will also serve to join the parts in permanent fashion. A still further object of the invention is to provide a decorative and utilitarian structure for sewing which will be economical of thread and in which threads of different quality may be employed so that the visible thread may be of one kind and the invisible thread of another kind, thus to further keep the cost at a minimum without sacrificing strength, appearance or usefulness. Another object is to provide a simple thread construction which may be made on a two-needle sewing machine without substantial modification thereof and which may easily be modified both in its transverse and longitudinal dimensions in accordance with the treatment desired.

in its broadest aspect the seam has a surface thread which crosses and recrosses the work in diagonally recurrent runs spaced longitudinally, integral loops which penetrate the work forming spaced parallel rows of loops at the underside thereof and backing threads passing through each row of loops. In the preferred form the seam comprises a pair of flexible facing threads having portions of predetermined length crossing and recrossing the work at regular recurrent intervals spaced longitudinally thereof, corresponding portions of the two threads crossing each other and integral portions penetrating the work forming loops at the underside thereof, the loops at opposite ends of the surface portions forming spaced parallel rows of loops. Successive loops of each row are formed from alternate ones of the surface threads and a pair of l backing threads are located at the underside of the work, one passing through the loops of each row of loops, the backing threads being substantially straight and parallel and locking the loops at the underside of the work. Decorative beading of circular or multiside cross section may be faggoted to the work by such stitching. The facing threads may be treated to correspond in color to the work to which it is to be applied or to be complementary thereto and of a size to afford the appearance desired while the backing thread may be made of an undyed and less expensive thread since it is on the back side of the work and since it does not have to have a good appearance.

The invention will now be described in greater detail with reference to the accompanying drawings wherein:

Fig. l is a perspective view diagrammatically illustrating the construction of the stitch;

Fig. 2 is a plan View of a seam on the finish side;

Fig. 3 is a plan view of the reverse side;

Fig. 4 is a plan view of the finished side showing a seam with but one finished thread;

Fig. 5 is a fragmentary vertical section showing a decorative element attached to sheet material by means of the seam;

Fig. 6` is a perspective view showing a decorative element of semi-circular cross section attached to sheet material;

Fig. 7 is a vertical section through a sheet showing another way of employing the seam for attaching a decorative clement thereto; and

Fig. 8 shows a vertical section through two sheets joined in overlapping relation by the seam.

Referring to the drawings, Fig. 1, there is shown sheet material l0, for example, a piece of upper leather such as used in making shoes or a suitable leather for making pocketbooks, belts and so forth, to which is applied either for ornamental or utilitarian purposes a seam 12. The seam is comprised of two upper threads 14 and 16 and two lower threads 13 and 2t). The course of the upper thread 14 starting at the left side of Fig. l is illustrated diagrammatically and in somewhat exagerated form as passing vertically downward from the upper side of the sheet material through a needle hole a through the underside of the sheet then back again through the same needle hole leaving a loop 22 at the underside of the sheet, diagonally across the sheet thereby laying a portion 24 on the face of the sheet, vertically downward through a needle hole b `and then back again through the same hole to leave a loop 26 on the underside of the sheet, then diagonaily across the sheet in the opposite direction to leave a portion 2S on the face of the sheet, then vertically downward through a needle hole a and upwardly through the saine hole to leave another loop 22 whereupon the operation is repeated so as to form successive lengths 24 and 2S crossing and recrossing the sheet to form longitudinally spaced zigzag stitches on the face of the sheet. Simultaneously, with the formation of the foregoing zigzag stitch the thread 16 follows a similar course, first penetrating the fabric through a stitch hole c then returning through the same hole to leave a loop 30, thence diagonally across the surface of the sheet to lay a portion 32 thereon which crosses the previously laid length 24, thence downwardly through a needle hole d and then upwardly to leave a loop 34, thence transversely of the sheet to lay a portion 36 across its face which intersects the portion 23 of the thread 14, thence downwardly through the needle hole c. The crossing and recrossing of the threads i4 and 16 may be continued for as many repeats as is desired. The loops at the opposite side of the sheet at opposite ends of the portions 24, 2S, 32 and 36, laid on the surface of the sheet are locked at the underside of the sheet by the threads iS and 20, one of which passes through the successive loops 22 and 34 and the other through the successive loops 30 and 26.

The needle holes a, b, c and d referred to above are made by the needle itself as it carries the thread through the work however these holes could be made prior to the formation of the seam if desired, for example, by an awl. The awl might be a part of the sewing machine itself and be operated in advance of the needle to punch the required holes. The foregoing stitch formation may be made in any suitable manner but as practiced herein is made by a sewing machine having a pair of spaced needles vertically reciprocal in unison which carry a pair of threads through the fabric to form loops on the underside and is provided with a pair of shuttles located beneath the feed plate for placing the threads through the loops as they are formed. The crossing of the threads is secured by a rotational oscillation of the needle bar about its vertical axis so as to reverse the positions of the needles at each penetration. The machine except for the pair of spaced needles and shuttles is of conventional construction and is provided with means for varying the oscillation of the needles so c tl as to compress the stitch widthwise and for varying the feed so as to compress the stitch lengthwise. If desired, by removing one needle a single zigzag thread 14 may be laid on the surface of the sheet material in place of the double cn'sscross as illustrated in Fig. 4.

While the seams shown in Figs. l, 2 and 3 are applied to a single sheet of material as ornamentation itself, it may be used for fastening other ornamental material to leather goods as shown in Figs. 5, 6 and 7. An ornamental beading 38 of rectangular or circular cross section, that shown (Fig. 5) being rectangular, may be made fast to the face of the sheet material 10 by the cross stitching 24 and 32.

In Fig. 6 a decorative element 40 of semi-circular cross section is shown attached to sheet material 10. In Figs. 5 and 6 the threads forming the seam do not penetrate the element being faggoted to the sheet material.

In Fig. 7 a dat strip 42 is shown attached by the cross thread 24 and 32 of the seam passing through the sheet material.

In Fig. 8 the seam is shown for attaching two overlapping portions of sheet material 10 and 1 together, for example, for forming a seam in the upper material of a shoe or other leather goods.

The special advantages of the seam as constructed are that it affords means which is both decorative and utilitarian, that it may be Varied almost infinitely in appearance by compressing or expanding it both widthwise and lengthwise, by changing the size, color and twist of the thread, that it is economical because the cost of the relatively expensive facing thread which appears on the right side is at least partially compensated for by the use of a comparatively inexpensive backing thread, that it may be used to attach decorative elements to work and that it can be performed on a conventional sewing machine with very little modification of the operating parts there of.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claim.

I claim:

A multithread lock stitch seam joining exible sheet material in which there is a face and a back comprising a pair of facing threads, said facing threads having portions of corresponding length crossing each other on the face ot' the material, loops at the ends of the portions, said loops penetrating the material with successive loops from alternate threads lying along spaced parallel lines at the back of the material, and a backing thread at the back of the material passing through the lops of each line of loops so as to lock the loops at the back, each backing thread being continuous and substantially straight and said backing threads being parallel.

References Cited in the tile of this patent UNITED STATES PATENTS 203,300 Stribley May 7, 1878 844,320 Borton Feb. 19, 1907 1,718,156 Langa June 18, 1929 2,006,861 Grady July 2, 1935 2,322,523 Kierner l une 22, 1943 2,600,908 Nachman June 17, 1952 2,649,062 Nogler et al Mar. 18, 1953 FOREIGN PATENTS 725,819 Germany Aug. 13, 1942 

